Refrigerating apparatus



Dec. 28, 1937. A. D. KARR' REFRIGERATING APPARATUS Filed July 5, 1957 INVENTOR gz nmwmm H I S ATTORNEY.

Patented Dec. 28, 1937 UNITED STATES REFRIGERATING APPARATUS Alfred D. Karr, Newark, N. J., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application July 3, 1937, Serial No. 151,796

11 Claims.

This invention relates to refrigerating apparatus, but more particularly to plural stage evapcrating apparatus for vaporizing and cooling refrigerant and in which each stage comprises several cooling chambers.

An object of the invention is to simplify the construction and operation of plural stage evaporating apparatus.

Another object of the invention is to combine the advantages of stage evaporation throughout a range of capacity adjustment of the unit as a whole.

Another object is to produce plural stage evaporating apparatus in which the refrigerating capacity of any stage may be varied.

A further object is to assure continuous supply of refrigerant to active chambers of a refrigerating stage and to obviate exposure of refrigerant to undue heating effects in inactive chambers of a stage.

An additional object is to obviate inequalities of temperature between active chambers of a refrigerating stage.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing, the figure is an elevation,

partly in section, of refrigerating apparatus conpractice of thestructed in accordance with the invention.

Referring more particularly to the drawing, 20 designates in general plural stage evaporating apparatus comprising primary stage evaporator chambers 23, 25, and 21, and secondary stage evaporator chambers 24, 26, and 28.

An inlet pipe 31 leading from a source of refrigerant (not shown) .has branches (not shown) opening into each of "the primary stage chambers 23, 25, and 21, and each of these chambers is grouped and connected in series with a secondary stage chamber 24, 26, and 28, respectively, by a passage 4' I. Refrigerant passes progressively through primary and secondary chambers of a group and leaves the secondary stage chambers by outlets 36 which open into a discharge conduit 32. A pump 33 connected to the conduit serves to impel chilled refrigerant to a place of use (not shown). It will be understood that additional stages and groups of chambers may be provided, if desired.

Vapor evacuators 2i and 22, shown as steam ejectors, are connected to the chambers of the primary and secondary stages, respectively, and serve to reduce the pressure in the chambers to cause vaporization and chilling of refrigerant under successively lower conditions of temperature and pressure in the stages.

In practice the chambers are conveniently formed within a shell 55 of suitable shape and are herein disposed in a horizontal line at equal elevations. The shell 55 is closed at the ends and at intervals along its length by transverse vertical partitions 30 and enclosed between every two immediately adjacent partitions 30 is one of the groups of chambers. Transverse vertical partitions 29 positioned between adjacent partitions 30 cooperate with the latter partitions and with the walls of the shell 55 to separate and define the chambers of a group.

In the practice of the invention refrigerant enters each chamber through an inlet well opening into the chamber above the refrigerant level therein and the well serves under certain conditions to preclude the admission of refrigerant to the chamber. Within each primary stage chamber 23, 25, and 21 a transverse vertical weir 36 extends upwardly from the bottom of the shell 55 between the partitions 29 and 30 and cooperates with the partition 30 and the side and bottom walls of the shell to define an inlet well 35 open at the top into the chamber. Ports 36 in the shell serve to connect the bottoms of the wells 35 to the branches of the inlet pipe 31. The

tops of the weirs 36 are considerably above the refrigerant levels in the chambers and serve as overflow means from which refrigerant falls to be exposed in more or less divided state to the reduced pressure in the chambers 23, 25, and 21.

The chambers 23, 25, and.2'l are in communication through the wells 35 and pipe 31 and the refrigerant columns in the wells are balanced against the pressures in the chambers and serve as seals therebetween. The ports 38 are sumciently below the tops of the weirs 36 that the pressure in any primary stage chamber 23, 25,

or 21 maybe increased to the discharge pressure of the ejectors to depress refrigerant below the top of the weir 36 of such a chamber without destroying the seal in the well.

Within each secondary stage chamber 24, 26, and 28 a transverse vertical weir 43 extends upwardly from the bottom of the shell 55 between the partitions 29 and 30 and cooperates with the partition 29 and the side walls of the shell to define an inlet well 42 open at the top into the chamber. Passages 4| defined at the bottoms of the partitions 29 between these partitions and the bottom of the-shell 55 serve to connect the bottoms of the wells 42 with the bottoms of the primary stage chambers 23, 25, and 2l. The tops 55 of the weirs-'43 are above the refrigerant levels in the secondary stage chambers and serve as overflow means from which refrigerant falls into these chambers.

The primary and secondary stage chambers of a group are in communication through a well 42 and passage 4| and the refrigerant columns in the well and in the primary stage chamber are balanced against the pressures in the chambers of the group and serve as seals therebetween. The passages 4| are sufilciently below the tops of the weirs 43 that the pressure in anychamber may be increased to the discharge pressure of the ejectors to depress refrigerant below its normal level in a well 42 or in a primary stage chamber without destroying the seal in the well 42. The tops of the weirs 43 are also considerably lower than the tops of the weirs of the primary stage chambers.

Ports 33 and 44 may be provided, if desired, 4

near the tops of the weirs 36 and 43, respectively, to deliver refrigerant to the chambers. A suitable baffle may also be provided in each chamber adjacent each weir to obviate entrainment of refrigerant in a liquid state in the stream of vapor flowing to .the ejectors 2| and 22.

Outlet ports 3| for chilled refrigerant in the bottoms of the secondary stage chambers 24, 25, and 28 open into vertical risers or branches 56 of the discharge conduit 32. These chambers communicate through the risers and conduit but are sealed by refrigerant therein, and the height of the risers, is sufllciently great that an increase of pressure in any secondary stage chamber to I the dischargepressure of the ejectors will not destroy the seals in the risers.

The steam ejectors 2| and 22, preferably identical and of usual form, are superposed on the shell 55 to communicate with the chambers through ports 49 in the top of the shell. A separate ejector is provided for each chamber and serves to remove and compress vapor from the chamber into a condenser 34.. For selective control of the ejectors, separate steam supply pipes 41, each provided with a valve 43, lead to the ejectors.

The condenser 34 may be of any well known construction, and may have a single condensing chamber into which all the ejectors discharge. The condensing chamber serves to condense vapor at the relatively high discharge pressure and temperature of the ejectors, and the casings of the ejectors define open passages (not shown) between the ports 49 and the condenser 34. When an ejector is inactive the pressure in the evaporator chamber is the pressure existing in the condenser.

In prior structures involving a group of evaporator chambers connected. in series it has been the practice to supply refrigerant to active chambers of the group by passing refrigerant continuously through all of the chambers. Complex devices, such as valves in the ejector casings or seetionalized condensers, have been required to obviate exposure of refrigerant in an inactive chamber to the heating effect of the hot vapor discharged by active ejectors. In the present invention such devices are notrequired since admission of refrigerant to an inactive chamber through the inlet well thereof is precluded, and means are provided for supplying refrigerant from an active primary stage chamber of one group to an active secondary stage chamber of another group. To this latter end the bottoms of the primary stage chambers 23, 25, and 21 of the groups are connected by an .open passage.

In the illustrated construction, such a passage final stage will include means such as the conduit 45.

The primary stage chambers 23, 25, and 21 are in communication through the conduit 45 but are sealed from each other by refrigerant therein. The ports 46 are also sufliciently below the normal level of refrigerant in these chambers that an increase of pressure in the chambers to the dis- 1 charge pressure of the ejectors will not breakthe seal.

The operation of the apparatus is as follows: Under full load conditions all of the valves 48 will be open and all of the ejectors 2| and 22 will be in action to reduce the pressure in all of the evaporator chambers.

Liquid refrigerant, which may be water, passing from the inlet pipe 31 through the inlet wells 35 will fall from the weirs 36 into the primary stage chambers 23, 25, and 21 and a portion of the refrigerant will vaporize owing to the reduced pressure. The heat of vaporization will be extracted from the main body of refrigerant and the temperature thereof will fall.

The refrigerant thus chilled will collect in the bottoms of the chambers 23, 25, and 21, fill the conduit 45 and flow through the passages 4| into the inlet wells 42. Refrigerant willthen fall from the weirs 43 into the secondary stage chambers 24, 26, and 28 and be exposed to further reduced pressure under the action of ejectors 22 to be furchilled refrigerant temperatures will occur in the primary stage chambers 23, 25, and 21 because the wells 35 communicate through the pipe 31. Any differential pressure existing between active primary stage chambers is balanced by the refrigerant columns or heads in the several wells and will automatically cause a lowering of the refrigerant level in the well 35 of the chamber tending to have higher pressure. The flow of refrigerant to this chamber and the heat load therein will, therefore, be automatically reduced, and the lower heat load will allow the ejector 2| for this chamber to again reduce the pressure.

Equal chilled refrigerant temperatures will also occur in the chambers of the secondary stage, for the wells 42 are in communication through the passages 4| and conduit 45, and any tendency for the pressure in active secondary stage chambers to vary with respect to each other will be overcome by a decrease in'the flow of refrigerant through the well 42 of the chamber tending to have the higher pressure.

.The conduit 45 thus serves to equalize the chilled refrigerant temperatures in the secondary stage chambers by governing the flow of refrigerant thereto. This characteristic of equal chilled refrigerant temperature throughout a stage is particularly valuable if temperature or other automatic regulation of the apparatus is to be practiced.

Under part load conditions the refrigerating capacity of the evaporating apparatus maybe reduced by shutting ofi some of the valves 48 of the ejectors 2i and 22 and this operation will also effect an immediate shut down of the evaporator chambers to which such ejectors are connected.

Assuming that the valves 48 for the ejectors 2i and 22 of the chambers 26 and 21, respectively, have been closed, the chamber 21 will then be subjected to the discharge pressure of the active ejectors by the backing up of vapor into the chamber from the condenser 34. The pressure differential between chamber 21 and the active primary stage chambers 23 and 25 will immediately stop the admission of refrigerant to the chamber 27 through its well 36, for refrigerant will be depressed below the top of the weir 36 of this well a distance equivalent to the said pressure differential as balanced through the pipe 31 by the refrigerant in the communicating wells 35.

The pressure'increase will also cause the refrigerant in the chamber 21 to take a level below the level of the refrigerant in the active primary stage chambers 23 and 25,and the difference in these levels will be equivalent to the difference between condenser pressure and the pressure in the active chambers 23 and 25 as balanced by refrigerant through the conduit 55.

The level of refrigerant in the chamber 21 will also be depressed below the level of refrigerant in the well 42 of the secondary stage chambers, and this difference in level will be equivalent to the difference between condenser pressure and the pressure in active secondary stage chamber 28 as balanced by refrigerant through the well 42 and passage 4|.

Cessation of refrigerant flow to the chamber 21, will cause all the refrigerant to be supplied by the pipe 31 to the wells 35 of the active chambers 23 and 25, and equality of chilled refrigerant 4,5 temperature between such chambers will be maintained as before.

There will also be no cessation in the flow of refrigerant to secondary stage chamber 28 which is grouped with and connected to receive refrig erant from chamber 21. For, immediately upon a cessation of refrigerant flow over the weir 35 into chamber 21, the conduit 45 will serve to supply refrigerant from the active primary stage chambers 23 and 25 through the port 46 in the bottom of chamber 21 to the passage 4| and the inlet well 42 of chamber 28.

Vapor under condenser pressure backing up through the casing of inactive ejector 22 into the secondary stage chamber 26 will create a pressure differential between this chamber and active secondary stage chambers 24 and 28. The admission of refrigerant to chamber 26 through its well 42 therefore stops. Refrigerant will be depressed below the top of the weir 43 of this well 42 a distance corresponding to the differencein head in the chambers 26 and 25.

Immediately upon this increase of pressure in the inactive chamber 26 the conduit 45 will serve to supply refrigerant from primary stage chamber 25 which is grouped with chamber 26 to the bottoms of primary stage chambers 23 and 21 andthence to the wells 42 of active secondary stage chambers 24 and 28.

In this way any active primary stage chamber may supply refrigerant to any active secondary stage chamber when normal admission of refrigerant to an inactive chamber has stopped. The action is completely automatic and occurs whenever a valve 48 is shut off. Practically no refrigerant in an inactive secondary stage is brought into intimate contact with hot vapor, and there is no material re-heating of the refrigerant.

I claim:--

1. In refrigerating apparatus, an evaporator comprising primary chambers and secondary chambers in constant communication with the primary chambers, means to admit refrigerant to the chambers, means for rendering any chamber inactive, and means for sup-plying refrigerant from an active primary chamber to any inactive primary chamber.

2. In refrigerating apparatus, an evaporator comprising primary chambers and secondary chambers in constant communication with the primary chambers, means to admit refrigerant to the chambers, means toselectively reduce the pressure in any chamber and to render the chamber inactive, and means for supplying refrigerant from an active primary chamber to an inactive primary chamber.

3. In refrigerating apparatus, an evaporator comprising primary chambers and. secondary chambers in constant communication with the primary chambers, means to admit refrigerant to the chambers, means to reduce the pressure in the chambers, means to render any chamber inactive, and means for supplying refrigerant from any active primary chamber to any inactive primary chamber.

4. In refrigerating apparatus, an evaporator comprising primary chambers and secondary chambers in constant communication with the primary chambers, means to admit refrigerant to the chambers, means to reduce the pressure in the chambers, means to render any chamber inactive, and means defining a passage to supply refrigerant from any active primary chamber to any inactive primary chamber,

5. In refrigerating apparatus, an evaporator comprising primary chambers and secondary chambers in constant communication with the primary chambers, means to admit refrigerant to the chambers, means to reduce the pressure in any chamber, means to render the last said means inoperative for any chamber, means responsive to a pressure increase in any chamber to render the chamber inactive, and means to supply refrigerant from an active primary chamber to any inactive primary chamber.

6. In refrigerating apparatus evaporator means comprising primary chambers and secondary chambers, an inlet well in each chamber, means common to the wells in the primary stage chambers to supply refrigerant thereto, means to supply refrigerant from a primary stage chamber to the well in a secondary stage chamber, evacuator means to reduce the pressure in the chambers, means to render any chamber inactive, means to increase the pressure in any active chamber to render it inactive and to preclude the supply of refrigerant through the inlet well thereof, and means including a passage connecting the bottoms of the primary chambers and serving to supply refrigerant from any active primary chamber to the inlet well in any active secondary chamber.

7. In refrigerating apparatus, evaporator means comprising primary chambers and secondary chambers, means to admit refrigerant to the primary chambers, means to admit refriger- 4- moans ant from a primary chamber a secondary chamber, means to reduce the pressure in the chambers, means to govern the admission of refrigerant to the primary chamber, and means associated with the primary chambers to supply refrigerant from an active primary chamber to an active secondary stage chamber through an inactive primary chamber.

8. In refrigerating apparatus, evaporator means comprising primary chambers and sec ondary chambers, evacuator means to selectively reduce the pressure in the chambers, an inlet well in each chamber, inlet means common to the wells in the primary chambers to supply refrigerant thereto, outlet means to supply refrigerant from a primary chamber to the well in a secondary chamber, and means defining a passage interconnecting the bottoms of the primary chambers.

9. In refrigerating apparatus, evaporator means having groups of chambers, each group comprising a primary chamber in communication with a secondary chamber, means to reduce the pressure in the chambers and to render any I chamber inactive, and means for supplying refrigerant from an active primary chamber of one group to an active secondary chamber of another group having an inactive primary chamber.

10. In refrigerating apparatus, an evaporator means having groups of chambers, each group comprising a primary chamber in communication with a secondary chamber, means for passing refrigerant progressively through the primary and secondary chambers of a group, means to reduce the pressure in the chambers, means to render any chamber inactive, and means for supplying refrigerant from an active primary chamber of one group to an active secondary chamber of a group having an inactive primary chamber.

11. In refrigerating apparatus, evaporator means comprising primary chambers and secondary chambers in communication with the primary chambers, means to admit refrigerant to the primary chambers, means to reduce the pressure in the chambers, means to render the last .means inoperative and to thereby increase the pressure in an active chamber to render it inactive responsive to the pressure increase to preclude the admission of refrigerant to an inactive chamber, and means responsive to the pressure increase in an inactive chamber for supplying refrigerant from any active primary chamber to any inactive primary chamber.

ALFRED D. KARR. 

